pgevent.c

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/*-------------------------------------------------------------------------
 *
 * pgevent.c
 *      Defines the entry point for pgevent dll.
 *      The DLL defines event source for backend
 *
 *
 * IDENTIFICATION
 *    src/bin/pgevent/pgevent.c
 *
 *-------------------------------------------------------------------------
 */


#include <windows.h>
#include <olectl.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>

/* Global variables */
HANDLE      g_module = NULL;    /* hModule of DLL */

/*
 * The event source is stored as a registry key.
 * The maximum length of a registry key is 255 characters.
 * http://msdn.microsoft.com/en-us/library/ms724872(v=vs.85).aspx
 */
char        event_source[256] = "PostgreSQL";

/* Prototypes */
HRESULT     DllInstall(BOOL bInstall, LPCWSTR pszCmdLine);
STDAPI      DllRegisterServer(void);
STDAPI      DllUnregisterServer(void);
BOOL WINAPI DllMain(HANDLE hModule, DWORD ul_reason_for_call, LPVOID lpReserved);

/*
 * DllInstall --- Passes the command line argument to DLL
 */

HRESULT
DllInstall(BOOL bInstall,
           LPCWSTR pszCmdLine)
{

    if (pszCmdLine && *pszCmdLine != '\0')
        wcstombs(event_source, pszCmdLine, sizeof(event_source));

    /*
     * This is an ugly hack due to the strange behavior of "regsvr32 /i".
     *
     * When installing, regsvr32 calls DllRegisterServer before DllInstall.
     * When uninstalling (i.e. "regsvr32 /u /i"), on the other hand, regsvr32
     * calls DllInstall and then DllUnregisterServer as expected.
     *
     * This strange behavior forces us to specify -n (i.e. "regsvr32 /n /i").
     * Without -n, DllRegisterServer called before DllInstall would mistakenly
     * overwrite the default "PostgreSQL" event source registration.
     */
    if (bInstall)
        DllRegisterServer();
    return S_OK;
}

/*
 * DllRegisterServer --- Instructs DLL to create its registry entries
 */

STDAPI
DllRegisterServer(void)
{
    HKEY        key;
    DWORD       data;
    char        buffer[_MAX_PATH];
    char        key_name[400];

    /* Set the name of DLL full path name. */
    if (!GetModuleFileName((HMODULE) g_module, buffer, sizeof(buffer)))
    {
        MessageBox(NULL, "Could not retrieve DLL filename", "PostgreSQL error", MB_OK | MB_ICONSTOP);
        return SELFREG_E_TYPELIB;
    }

    /*
     * Add PostgreSQL source name as a subkey under the Application key in the
     * EventLog registry key.
     */
    _snprintf(key_name, sizeof(key_name),
            "SYSTEM\\CurrentControlSet\\Services\\EventLog\\Application\\%s",
              event_source);
    if (RegCreateKey(HKEY_LOCAL_MACHINE, key_name, &key))
    {
        MessageBox(NULL, "Could not create the registry key.", "PostgreSQL error", MB_OK | MB_ICONSTOP);
        return SELFREG_E_TYPELIB;
    }

    /* Add the name to the EventMessageFile subkey. */
    if (RegSetValueEx(key,
                      "EventMessageFile",
                      0,
                      REG_EXPAND_SZ,
                      (LPBYTE) buffer,
                      strlen(buffer) + 1))
    {
        MessageBox(NULL, "Could not set the event message file.", "PostgreSQL error", MB_OK | MB_ICONSTOP);
        return SELFREG_E_TYPELIB;
    }

    /* Set the supported event types in the TypesSupported subkey. */
    data = EVENTLOG_ERROR_TYPE | EVENTLOG_WARNING_TYPE | EVENTLOG_INFORMATION_TYPE;

    if (RegSetValueEx(key,
                      "TypesSupported",
                      0,
                      REG_DWORD,
                      (LPBYTE) &data,
                      sizeof(DWORD)))
    {
        MessageBox(NULL, "Could not set the supported types.", "PostgreSQL error", MB_OK | MB_ICONSTOP);
        return SELFREG_E_TYPELIB;
    }

    RegCloseKey(key);
    return S_OK;
}

/*
 * DllUnregisterServer --- Instructs DLL to remove only those entries created through DllRegisterServer
 */

STDAPI
DllUnregisterServer(void)
{
    char        key_name[400];

    /*
     * Remove PostgreSQL source name as a subkey under the Application key in
     * the EventLog registry key.
     */

    _snprintf(key_name, sizeof(key_name),
            "SYSTEM\\CurrentControlSet\\Services\\EventLog\\Application\\%s",
              event_source);
    if (RegDeleteKey(HKEY_LOCAL_MACHINE, key_name))
    {
        MessageBox(NULL, "Could not delete the registry key.", "PostgreSQL error", MB_OK | MB_ICONSTOP);
        return SELFREG_E_TYPELIB;
    }
    return S_OK;
}

/*
 * DllMain --- is an optional entry point into a DLL.
 */

BOOL        WINAPI
DllMain(HANDLE hModule,
        DWORD ul_reason_for_call,
        LPVOID lpReserved
)
{
    if (ul_reason_for_call == DLL_PROCESS_ATTACH)
        g_module = hModule;
    return TRUE;
}